CFB Service Failure

The CFB service is enabled for number 3888, and the forwarded-to number is set to 2726. An outer-office user uses number 8000 to make a call to long number 81760888 corresponding to number 3888, and the call is connected. When another outer-office user uses number 8001 to make a call to long number 81760888, the calling party can hear the ringback tone, but the phone whose number is 2726 does not ring.

Handling Process

Step 1 Pick up the phone whose number is 2726, dial *128#, and verify that the local phone number is 2726.

Step 2 Check the IP address of the device with which number 3888 is registered.

Step 3 Use the LMT configuration wizard to view the services enabled for number 3888.

show subscriber dn 3888
It is found that the PBX group line selection service is enabled for number 3888, and number 2982 belongs to the same PBX group as number 3888. Number 3888 is the main number of the PBX group. When there is an incoming call to the phone whose number is 3888 and the phone is busy, the call is automatically forwarded to number 2982. Therefore, the calling party can hear the ringback tone, but the phone whose number is 2726 does not ring.